Process for retaining moisture in cooked animal muscle

ABSTRACT

A meat or fish composition which retains moisture during cooking is provided. A dry protein mixture or an aqueous acidic protein solution derived from animal muscle tissue is added to the meat or fish prior to cooking. The dry protein mixture and aqueous acidic protein solution comprise myofibrillar proteins and sarcoplasmic proteins substantially free of myofibrils and sarcomeres.

REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of application Ser. No.10/252,873, filed Sep. 24, 2002 now abandoned.

BACKGROUND OF THE INVENTION

This invention relates to a process for retaining liquid in cooked food.More particularly, this invention relates to such a process whichutilizes animal muscle protein to retain moisture in food and to thefood product utilized in the process.

Prior to the present invention, meat or fish cooked at an elevatedtemperature loses its moisture to the surrounding atmosphere. In sodoing, the cooked meat or fish undesirably loses its natural or addedflavors so that it becomes less tasteful. Fluid loss during cooking ofmeat or fish can range up to 30% to 40% by weight based upon the weightof the meat or fish prior to cooking. A prior solution for retainingmoisture in the meat or fish without additives took the form of wrappingthe meat or fish in a solid moisture barrier such as aluminum foil. Thissolution is undesirable since the surface of the meat or fish remainssoft rather than having a desirable crust.

Prior attempts to retain moisture in cooked meat or fish with additiveshave included the use of sodium tripolyphosphate, a coating of fat freeflour, based, batter containing an egg white substitute (U.K. PatentApplication 2,097,646), water-in-oil emulsion (U.S. Pat. No. 3,406,081),protein or protein isolate and a fat (U.S. Pat. Nos. 4,031,261 and4,935,251), milk solids (U.S. Pat. No. 2,282,801) and lecithin (U.S.Pat. Nos. 2,470,281 and 3,451,826).

Accordingly, it would be desirable to provide a form of fish or meatwhich can be cooked while retaining its moisture and natural or addedflavors without the use of a solid moisture barrier so that the surfaceof the cooked meat or fish could become crusty during cooking. Inaddition, it would be desirable to provide such a form of fish or meatwhich is not less nutritional than the original fish or meat or which iseven more nutritional than the original fish or meat to be cooked. Inaddition, it would be desirable to provide such a form of fish or meatwherein the majority of moisture or added flavors or spices in theuncooked fish or meat is retained during cooking.

SUMMARY OF THE INVENTION

In accordance with this invention, animal muscle tissue to be cooked iscoated or admixed or injected with a dry protein mixture or an aqueousacidic solution of protein mixture derived from animal muscle tissuecomprising a mixture of myofibrillar proteins and sarcoplasmic proteinsobtained by one of the processes disclosed in U.S. Pat. Nos. 6,005,073;6,288,216; 6,136,959 and/or 6,451,975 all of which are incorporatedherein by reference in their entirety. By the phrase, “dry proteinmixture” as used herein is meant a dehydrated, protein mixture ofmyofibrillar proteins and sarcoplasmic proteins derived from animalmuscle tissue and which is obtained from an aqueous acid solution (lessthan or equal to pH 3.5) or an aqueous alkaline solution (greater thanor equal to pH 10.5) and having a final pH of about 4.5 or less orbetween pH 6.5 and 8.5. The dry protein mixture also contains less thanabout 15 weight percent water, preferably between about 3 and 10 weightpercent water and most preferably between about 3 and 7 weight percentwater based on the total weight of the protein mixture and water. Whilea dry protein mixture containing 0% water is useful in the presentinvention, dry powders, in general, containing 0 to 3 weight percentwater can be dangerous to process on a commercial scale since they havean explosive nature. Solid mixtures of myofibrillar proteins andsarcoplasmic proteins containing greater than about 15 weight percentwater based on total weight of the protein mixture and water areundesirable in this invention since they are microbially unsound. Inaddition, it has been found that a mixture of myofibrillar proteins andsarcoplasmic proteins derived from animal muscle tissues having a pHgreater than 4.5 to about 6.5 are not useful in the present inventionsince they do not retain significant moisture in cooked meat or fish.Furthermore, such proteins derived from solutions having a pH of 8.5 orabove are not useful since they can be physiologically harmful.

By the phrase “aqueous acidic protein solution” as used herein is meantan aqueous solution of myofibrillar proteins and sarcoplasmic proteinsderived from animal muscle tissue and having a pH of 3.5 or less andpreferably between about 2.5 and about 3.5 but not so low as toadversely affect the protein functionality. The aqueous acidic proteinsolution can be obtained directly from animal muscle tissue acidic bythe processes described below or by dissolving the dry protein mixturein water or in a pharmaceutically or food grade acceptable aqueousacidic solution.

In accordance with this invention the dry protein mixture ofmyofibrillar proteins and sarcoplasmic protein, in powder form,dehydratred form or small particulate form is applied to the surface ofanimal muscle tissue to be cooked or is mixed with the animal muscletissue (ground, minced as thinly sliced) to be cooked such as hamburgeror sausage. Alternatively, the aqueous acidic protein solution can beinjected into the muscle tissue of fish or meat or it can be applied tothe surface of the fish or meat or it can be mixed with the fish ormeat. The fish or meat containing the dry protein mixture then can becooked at elevated temperature in the absence of a solid moisturebarrier while retaining a substantial majority of its original moisture.The difference in weight between meat or fish treated in accordance withthis invention compared with fish or meat not injected, mixed or coatedwith the dry protein mixture or aqueous acidic protein solution isbetween about 4 and about 21%, more usually, between about 4 and about10%.

DESCRIPTION OF SPECIFIC EMBODIMENTS

In accordance with this invention, animal muscle to be cooked is coated,admixed and/or injected with a dry protein mixture or an aqueous acidicprotein solution of myofibrillar proteins and sarcoplasmic proteinsderived from animal muscle tissue and obtained by the processesdisclosed in U.S. Pat. Nos. 6,005,073, 6,288,216, 6,136,959 and6,451,975 all of which are incorporated herein by reference in theirentirety. This dry protein mixture is obtained by one of four processes.In two processes, (acid processes) animal muscle tissue is formed intosmall tissue particles which are then mixed with sufficient acid to forma solution of the tissue having a pH of 3.5 or less, but not such a lowpH as to adversely modify the animal tissue protein. In one of these twoprocesses, the solution is centrifuged to form a lowest membrane lipidlayer, an intermediate layer of aqueous acidic protein solution and atop layer of neutral lipids (fats and oils). The intermediate layer ofaqueous acidic protein solution then is separated from the membranelipid layer or from both the membrane lipid layer and the neutral lipidlayer. In a second of these two processes, no centrifugation step iseffected since the starting animal muscle tissue contains lowconcentrations of undesired membrane lipids, oils and/or fats. In bothprocesses, the protein mixture is free of myofibrils and sarcomeres. Inboth processes, the protein in the aqueous acidic protein solution isrecovered after centrifugation (when used) by drying the aqueous acidicsolution, such as by evaporation, spray drying or lyophilization to formthe dry protein mixture having the low pH it had when it was dissolvedin the aqueous acidic protein solution. Alternatively, the aqueousacidic protein solution can be utilized with the uncooked meat or fishwithout drying. It is preferred to utilize one of these two acidprocesses to obtain the dry protein mixture or the aqueous acidicprotein solution. In another alternative process, the protein in theaqueous acidic protein solution can be precipitated and recovered andmixed with a pharmaceutically acceptable or food grade acid to form anaqueous acidic protein solution of a desired viscosity. This latteralternative process is particularly suitable for forming an aqueousacidic protein solution that can be injected into meat or fish.

In two other processes, (alkaline processes) animal muscle tissue isformed into small tissue particles which are then mixed with sufficientaqueous base solution to form a solution of the tissue wherein at least75% of the animal muscle protein is solubilized, but not such a high pHas to adversely modify the animal tissue protein. In one process, thesolution is centrifuged to form a lowest membrane lipid layer, anintermediate aqueous protein rich layer and a top layer of neutrallipids (fats and oils). The intermediate aqueous protein-rich layer thenis separated from the membrane lipid layer or from both the membranelipid layer and the neutral lipid layer. In a second process, nocentrifugation step is effected since the starting animal muscleproteins contain low concentrations of undesired membrane lipids, oilsand/or fats. In both processes, the protein mixture is free ofmyofibrils and sarcomeres. In both processes, the pH of the protein-richaqueous phase can be lowered to a pH below about 3.5, preferably betweenabout 2.0 and 3.5. In both processes, the protein in the aqueous acidicsolution is recovered after centrifugation (when used) by drying theaqueous acidic protein solution, such as by evaporation, spray drying orlyophilization to form a powder product having the low pH it had when itwas dissolved in the aqueous acidic solution. Alternatively, the aqueousacidic protein solution can be applied directly to the meat or fishwithout drying. The protein in aqueous basic solution having a pH above8.5 and recovered after centrifugation (when used) is not dried, such asby spray drying or lyophilization to form a powder product since thesepowders can be a source of health problems to a consumer in contrast tothe dry composition recovered from the aqueous acidic solution discussedabove. In addition, the aqueous basic protein solution is not useful inthe present invention for the same health problem reason. In one aspectof these two other processes, the pH of the basic solution can belowered to about 5.5 to precipitate the protein. The pH of theprecipitated protein then is raised to between 6.5 and 8.5 and a solidproduct is recovered such as by drying including spray drying,lyophilization or evaporation or which can be comminuted and applied tothe fish or meat. In another aspect of this process, the precipitatedprotein can be mixed with a pharmaceutically acceptable or food gradeacid to form an aqueous acidic protein solution of a desired viscosity.The latter process is particularly suitable for forming an aqueousacidic protein solution that can be injected into meat or fish.

The dry protein mixture or the aqueous acidic protein solution then isapplied to, admixed with and/or injected into the meat or fish. The dryacidic protein mixture or aqueous acidic protein solution can be appliedalone or in admixture with conventional food or nutritive additives suchas breading or batter coatings, spice dry rubs, cracker meal, corn mealor the like. It is preferred to utilize the aqueous acidic proteinsolution, with or without food or nutritional additives, for injection.The dry protein mixture and/or aqueous acidic protein solution can becoated on the surface of the meat or fish with an applicator or can becoated by tumbling the meat or fish in the solution or in a marinadecontaining the acidic aqueous protein solution or dry acidic proteinmixture in a tumbling or vacuum tumbling apparatus.

In summary, the dry protein mixture or the aqueous acidic proteinsolution utilized in the present invention can be obtained by thefollowing methods:

1. Reduce the pH of comminuted animal muscle tissue to a pH less thanabout 3.5 to form an acidic protein solution, centrifuge the solution toform a lipid-rich phase and an aqueous phase and recover an aqueousacidic protein solution substantially free of membrane lipids that canbe used in this invention.

2. Spray dry the aqueous acidic protein solution obtained by method 1 toform a dry protein mixture substantially free of membrane lipids thatcan be used in the present invention.

3. Lyophilize the aqueous acidic protein solution obtained by method 1to form the dry protein mixture substantially free of membrane lipidsthat can be used in the present invention.

4. Increase the pH of the aqueous acidic protein solution from method 1to about pH 5.0-5.5 to effect precipitation of the proteins and thenreadjust the protein back to a pH of about 4.5 or less using acid in aminimum volume to concentrate the aqueous acidic protein solution tobetween 1.6-15% protein.

5. Reduce the pH of comminuted animal muscle tissue to form an aqueousacidic protein solution that can be used in the present invention.

6. Spray dry the aqueous acidic protein solution obtained by method 5 toform the dry protein mixture that can be used in the present invention.

7. Lyophilize the aqueous acidic protein solution obtained by method 5to form the dry protein mixture that can be used in the presentinvention.

8. Increase the pH of the aqueous acidic protein solution from method 5to about pH 5.0-5.5 to effect precipitation of the proteins and thenreadjust the protein back to a pH of about 4.5 or less using acid in aminimum volume to concentrate the aqueous acidic protein solution tobetween about 1.6-15% protein.

9. Increase the pH of comminuted animal muscle tissue to a pH aboveabout 10.5, centrifuge the solution to form a lipid-rich phase and anaqueous phase and recover an aqueous basic protein solution. In oneembodiment, reduce the pH of the aqueous basic solution to a pH of lessthan about 3.5 to obtain an aqueous acidic protein solutionsubstantially free of membrane lipids that can be used in thisinvention. In a second embodiment, reduce the pH of the aqueous basicsolution to about 5.0-5.5 to precipitate the protein, raise the pH ofthe precipitated protein to 6.5-8.5, dry and comminute the protein. In athird embodiment, reduce the pH of the aqueous basic solution to about5.0-5.5 to precipitate the protein, lower the pH of the precipitatedprotein to a pH of 4.5 or less to form a concentrated aqueous acidicsolution and use the concentrated aqueous acidic solution or dry thesolution and use the recovered dry protein.

10. Spray dry the aqueous acidic protein solution obtained by method 9to form a dry acidic protein mixture substantially free of membranelipids that can be used in the present invention.

11. Lyophilize the aqueous acidic protein solution obtained by method 9to form the dry acidic protein mixture substantially free of membranelipids that can be used in the present invention.

12. Increase the pH of the aqueous, acidic protein solution from method9 to about pH 5.0-5.5 to effect precipitation of the proteins and thenreadjust the protein back to a pH of about 4.5 or less using acid in aminimum volume to concentrate the aqueous acidic solution to between1.6-15% protein.

13. Increase the pH of comminuted animal muscle tissue to a pH aboveabout 10.5 to form an aqueous basic protein solution. In one embodiment,reduce the pH of the basic solution to below about 3.5 to form anaqueous acidic protein solution that can be used in the presentinvention. In a second embodiment, reduce the pH of the aqueous basicsolution to about 5.0-5.5 to precipitate the protein, raise the pH ofthe precipitated protein to 6.5-8.5, dry and comminute the protein. In athird embodiment, reduce the pH of the aqueous basic solution to about5.0-5.5 to precipitate the protein, raise the pH of the precipitatedprotein to 6.5-8.5, dry and comminute the protein. In a thirdembodiment, reduce the pH of the aqueous basic solution to about 5.0-5.5to precipitate the protein, lower the pH of the precipitated protein toa pH of 4.5 or less to form a concentrated aqueous acidic solution anduse the concentrated aqueous acidic solution or dry the solution and usethe recovered dry protein.

14. Spray dry the aqueous acidic solution obtained by method 13 to forma dry acidic protein mixture that can be used in the present invention.

15. Lyophilize the aqueous acidic solution obtained by method 13 to formthe dry acidic protein mixture that can be used in the presentinvention.

The protein products utilized in the present invention compriseprimarily myofibrillar proteins that also contains significant amountsof sarcoplasmic proteins. The sarcoplasmic proteins in the proteinproduct admixed with, injected into or coated on the animal muscletissue comprises above about 8%, preferably above about 10%, morepreferably above about 15% and most preferably above about 18%, up toabout 30% by weight sarcoplasmic proteins, based on the total weight ofprotein in the dry acidic protein mixture or aqueous acidic proteinsolution.

In accordance with this invention the dry protein mixture ofmyofibrillar proteins and sarcoplasmic proteins, in powder form, smallcoarse particle or dehydrated form is applied to the surface of animalmuscle to be cooked, or is mixed with the animal muscle tissue to becooked such as hamburger, sliced reformulated beef or sausage. The term“a surface” as used herein is a surface of the fish or meat which ispositioned 90 degrees from an adjacent surface or surfaces of the meator fish. In addition, the term “a surface” can comprise the connectingsurface connecting two adjacent surfaces positioned 90 degrees from eachother. Preferably, the entire surface of the meat or fish is coated withthe dry acidic protein mixture or aqueous acidic protein solution. Thecoated fish or meat then can be cooked at elevated temperature whileretaining a substantial majority of its original moisture.

In one aspect of this invention, particulate meat or fish such as groundmeat or fish, e.g. hamburger, is mixed with the dry protein mixturecomprising myofibrillar proteins and sarcoplasmic proteins at a weightratio usually comprising about 0.03 to about 18% weight of the proteinmixture based on the weight of the uncooked meat or fish, preferablybetween about 0.5 and 10% weight based on the weight of uncooked meat orfish and most preferably comprising between about 0.5 to about 5% weightbased on the weight of the uncooked meat or fish. In addition, theaqueous acidic protein solution can be added to the meat or fish in thesame ratios based on the weight of protein in the solution. When the dryprotein mixture and/or aqueous acidic protein solution is applied to atleast one surface of the meat or fish or it is applied by injection, theamount of the protein mixture added is the same weight ratio as setforth above when mixed with ground meat or fish. When utilizing lessthan about 0.03% weight dry protein mixture or aqueous acidic proteinsolution, effective moisture retention is not observed. When utilizinggreater than about 15% weight dry protein mixture or aqueous acidicprotein solution, the cooked meat or fish can become undesirably hard.

The animal muscle tissue which is modified in accordance with thisinvention comprises meat and fish, including shell fish. Representativesuitable fish include deboned flounder, sole, haddock, cod, sea bass,salmon, tuna, trout or the like. Representative suitable shell fishinclude shelled shrimp, crabmeat, crayfish, lobster, scallops, oysters,or shrimp in the shell or the like. Representative suitable meatsinclude ham, beef, lamb, pork, venison, veal, buffalo or the like;poultry such as chicken, mechanically deboned poultry meat, turkey,duck, a game bird or goose or the like either in fillet form or inground form such as hamburg. The meats can include the bone of theanimal when the bone does not adversely affect the edibility of the meatsuch as spare ribs, lamb chops or pork chops. In addition, processedmeat products which include animal muscle tissue such as a sausagecomposition, a hot dog composition, emulsified product or the like canbe coated, injected or mixed with the dry acidic protein mixture and/orthe aqueous acidic protein solution, or a combination of these proteinaddition methods. Sausage and hot dog compositions include ground meator fish, herbs such as sage, spices, sugar, pepper, salt and fillerssuch as dairy products as is well known in the art.

The fish or meat containing the dry protein mixture or aqueous acidicprotein solution then can be cooked in a conventional manner such as bybaking, broiling, deep fat frying, pan frying, in a microwave oven orthe like. It has been found that the cooked meat or fish provided inaccordance with this invention weighs between about 4% and about 21%,more usually between about 4% and about 9% by weight greater than cookeduntreated meat or fish starting from the same uncooked weight.

The following examples illustrate the present invention and are notintended to limit the same. Percent (%) in Tables 1-8 reflects thecomparative loss of moisture in the controls verses the moisture loss inthe compositions of this invention (moisture content of a composition ofthis invention/moisture content of control X 100).

EXAMPLE 1 Incorporation (Chicken Protein Isolate-acid)

Chicken protein isolate from myofibrillar and sarcoplasmic proteins wasproduced according to U.S. Pat. No. 6,005,073 (low pH) from chickenbreast muscle; and freeze-dried until it contained approximately 5%moisture. The aqueous acidic protein solution from which the dry proteinmixture was obtained had a pH of 2.68. The dry protein mixture (proteinisolate) was incorporated into fresh, ground beef (75% lean) by handkneading for 1 min and shaped into hamburgers of uniform size. Toapproximately one-quarter lb. of beef (exactly weighed) was added 0-1.5grams of the dried protein isolate. The hamburgers were pan-fried on anIwatani (Tokyo, Japan) portable butane grill on high temperature for atotal of 15 min (10 min then flipped and additional 5 min). The internalcenters of the hamburgers reached 150° F.±2° F. after cooking. Thecooked hamburgers were drained on paper towels for twenty seconds priorto weighing (two decimal places).

TABLE 1 Favorable difference in Muscle (g) Start hamburger TissueProtein wgt End wgt. Cooking gain* (Hamburger) isolate (g) (g) (g) loss(%) Pct. Pts./% 113.17 0.00 113.17 70.93 37.32 control 113.13 1.00114.13 82.26 27.92  9.40/134 113.02 1.50 114.52 84.11 26.55 10.77/141*versus control, not including the weight of the protein isolate

The hamburgers containing from 1-1.5 g protein isolate had improvedcolor, were shiny in appearance on the hamburger's interior, and hadmuch greater juiciness and better mouth-feel than the control. Nodiscernable differences were found between the exterior surfaces of thecontrol (0.00 g. Protein isolate) or the samples with added proteinisolate.

EXAMPLE 2 Incorporation (Cod Protein Isolate-acid)

Cod protein isolate from myofibrillar and sarcoplasmic proteins wasproduced according to U.S. Pat. No. 6,005,073 (low pH) from freshAtlantic cod muscle. The aqueous acidic protein solution recovered wasadjusted to pH 5.5 to enact protein precipitation. The pH of theprecipitate was then raised to pH 7.04 and freeze-dried until itcontained approximately 7% moisture. The dry protein mixture (proteinisolate) was incorporated into fresh, ground beef (75% lean) by handkneading for 1 min and shaped into hamburgers of uniform size. Toapproximately one-quarter lb. of beef (exactly weighed) was added 0-1.5grams of dried protein isolate. The hamburgers were pan-fried on anIwatani (Tokyo, Japan) portable butane grill on high temperature for atotal of 15 min (10 min then flipped and additional 5 min). The internalcenters of the hamburgers reached 155° F. ±2° F. after cooking. Thecooked hamburgers were drained on paper towels for twenty seconds priorto weighing (two decimal places).

TABLE 2 Favorable difference in hamburger Protein Start wgt End wgt.Cooking gain* Muscle (g) isolate (g) (g) (g) loss (%) Pct. Pts./% 113.050.00 113.05 81.40 28.00 control 113.01 0.50 113.51 89.64 21.03 6.97/133112.92 1.00 113.92 88.49 22.32 5.68/125 113.08 1.50 114.58 89.68 21.736.27/129 *Versus control, not including the weight of the proteinisolate

The hamburgers containing from 0.5-1.5 g protein isolate had improvedcolor, were shiny in appearance on the hamburger's interior, and hadmuch greater juiciness and better mouth-feel than the control. Nodiscernable differences were found between the exterior surfaces of thecontrol (0.00 g. Protein isolate) or the samples with added proteinisolate.

EXAMPLE 3 Incorporation (Chicken Protein Isolate-alkaline)

Chicken protein isolate from myofibrillar and sarcoplasmic proteins wasproduced according to U.S. Pat. No. 6,136,959 (high pH) from chickenbreast muscle. A dry protein isolate was obtained by precipitation at apH of 5.5 followed by a readjustment of the precipitate pH to pH 7.12and subsequently freeze dried. The dry protein mixture (protein isolate)was incorporated into fresh, ground beef (80% lean) by hand kneading for1 min and shaped into hamburgers of uniform size. To beef (exactlyweighed) was added 0 and 4.0 grams of dried protein isolate. Thehamburgers were cooked on high in a Sharp Carousel (1000 watt) microwaveoven for a total of 110 seconds (no flipping). The internal centers ofthe hamburgers reached 183° F.±4° F. after cooking. The cookedhamburgers were drained on paper towels for twenty seconds prior toweighing (two decimal places).

TABLE 3 Favorable difference in hamburger Protein Start wgt End wgt.Cooking gain* Muscle (g) isolate (g) (g) (g) loss (%) Pct. Pts./% 98.640.00  98.64 59.60 39.58 control 98.59 4.00 102.59 70.86 30.93 7.26/128*Versus control, not including the weight of the protein isolate

The hamburger containing 4 g protein isolate had improved color, wasshiny in appearance on the hamburger's interior, and had much greaterjuiciness and better mouth-feel than the control (0.00 g. Proteinisolate). No discernable differences were found between the exteriorsurfaces of the control or the samples with added protein isolate.

EXAMPLE 4 Incorporation (Chicken Protein Isolate-acid-adjusted to pH5.5)

Chicken protein isolate from myofibrillar and sarcoplasmic proteins wasproduced according to U.S. Pat. No. 6,005,073 (low pH) from freshchicken muscle and readjusted to pH 5.5. Moisture content of theprecipitate was 74%. The protein isolate was chopped in a Waring foodprocessor for 20 seconds to reduce size and was incorporated into fresh,ground chicken breast by hand kneading for 1 min prior to being shapedinto patties of uniform size. The chicken pieces were cooked on high inZipLock® disposable containers in a Sharp Carousel (1000 watt) microwaveoven for 20 seconds, flipped and microwaved an additional 20 seconds.The internal centers of the chicken pieces reached 190° F.±0° F. aftercooking. The cooked chicken pieces were drained on paper plates prior toweighing (two decimal places).

TABLE 4 Difference in hamburger Protein Start wgt End wgt. Cooking gain*Muscle (g) isolate (g) (g) (g) loss (%) Pct. Pts./% 53.93 0.00 53.9346.63 13.54 control 55.18 1.04 56.22 47.59 15.35 −1.81/85 54.09 2.6856.77 47.69 15.99 −2.45/85 53.45 4.09 57.54 49.89 13.30   0.24/102*Versus control, not including the weight of the protein isolate

Both the coated sample and the control had visible pooled water aroundthem after cooking and were very similar in appearance. This exampleillustrates that a 5.5 pH form of the protein isolate produced by theprocess of U.S. Pat. No. 6,005,073 is not useful in the presentinvention.

EXAMPLE 5 Coating (Chicken Protein Isolate-acid)

Chicken protein isolate from myofibrillar and sarcoplasmic proteins wasproduced according to U.S. Pat. No. 6,005,073 (low pH) from chickenbreast muscle. A dry protein isolate was obtained by precipitation at apH of 5.5 followed by a readjustment of the precipitates to pH 6.73 andsubsequently was freeze-dried until it contained approximately 5%moisture. Fresh chicken breasts were cut into uniform portions, weighedand pressed into a dish containing the dry protein mixture (proteinisolate) until coated (with varying amounts of coating). The coatedchicken pieces were cooked on high in ZipLock® disposable containers ina Sharp Carousel (1000 watt) microwave oven for 20 seconds, flipped andmicrowaved an additional 20 seconds. The internal centers of the chickenpieces reached 179° F.±0°, except for the control, which reached 172° F.after cooking. The cooked chicken pieces were drained on paper platesprior to weighing (two decimal places).

TABLE 5 Favorable difference in chicken Protein Start wgt End wgt.Cooking gain* Muscle (g) isolate (g) (g) (g) loss (%) Pct. Pts./% 53.050.00 53.05 45.56 14.12 control 49.65 0.97 50.62 47.62 5.93  8.19/23853.23 1.27 54.50 52.34 3.96 10.16/357 49.37 1.75 51.12 48.86 4.42 9.70/319 51.98** 0.77 52.75 49.92 5.36  8.76/263 *Versus control, notincluding the weight of the protein isolate **Coated only on the topsurface

The chicken pieces containing between 0.97-1.75 g protein isolate hadimproved color, were shiny in appearance on the chicken's interior, andhad much greater juiciness and better mouth-feel than the control. (0.00g. Protein isolate). The coated pieces retained their original size andshape, whereas the control was very shape distorted. A large pool ofmoisture was found in the control container and very little to none inthe coated pieces containers. The chicken piece coated on one-side onlyhad slight distortion in size and a small amount of pooled moisture wasfound in the container after cooking.

EXAMPLE 6 Coating (Chicken, Cod, & Pork Protein Isolate-acid)

Dry acidic protein mixtures (protein isolate) from chicken breast,Atlantic cod fillet, and pork loin containing myofibrillar andsarcoplasmic proteins were produced according to U.S. Pat. No. 6,005,073(low pH). Dry protein isolates were obtained by precipitation at pH'sabout 5.5 followed by readjustment of the precipitate's pH to aboutneutrality. The precipitates subsequently were freeze-dried. Atlanticcod isolate was manufactured using 0.1% (of the total water weight)sodium tripolyphosphate prior to homogenization as a metal chelatingantioxidant. Pieces to be coated were cut into uniform portions, weighedand pressed into a dish containing the dried protein isolates untilcoated (with varying amounts of coating). The coated chicken pieces werecooked on high in ZipLock® disposable containers in a Sharp Carousel(1000 watt) microwave oven at 20 second intervals until an internaltemperature in the centers of the muscle pieces reached 172° F. Thecooked pieces were drained on paper plates prior to weighing (twodecimal places).

TABLE 6 Favorable difference Type of in material Material protein Startwgt End wgt. Cooking gain* coated isolate (g) (g) loss (%) Pct. Pts./%Haddock Cod 63.73 63.01 1.13  3.98/452 Haddock — 49.69 47.65 5.11control Chicken Chicken 44.22 43.73 1.11 21.37/ Chicken — 42.34 32.8222.48 2025 control Chicken Pork 38.20 36.62 4.14  9.76/336 Chicken —36.69 31.59 13.90 control Cod Cod 158.21 153.22 2.15  4.35/303 Codcontrol — 122.93 114.93 6.51 Chicken** Chicken 81.04 71.64 11.60 6.26/154 Chicken 80.22 65.89 17.86 control *Versus control, notincluding the weight of the protein isolate **Baked at 350° F. for 15min.

The pieces containing protein isolate were shiny in appearance on theinterior and had much greater juiciness and better mouth-feel than thecontrols (0.00 g. Protein isolate). The coated pieces retained theiroriginal size and shape, whereas the controls were very shape distorted.Large pools of moisture were found in the controls containers and verylittle to none in the coated pieces containers.

EXAMPLE 7 Coating (Chicken Protein Isolate-acid-adjusted to pH 5.5)

Protein isolate from chicken breast myofibrillar and sarcoplasmicproteins was produced according to U.S. Pat. No. 6,005,073 (low pH) andreadjusted to pH 5.5. Moisture content of the precipitate was 74%. Onesample was freeze-dried at pH 5.5 until a moisture content ofapproximately 6%. Pieces to be coated were cut into uniform portions,weighed and pressed into a dish containing the pH 5.5 protein isolatesuntil coated (with varying amounts of coating). The coated chickenpieces were cooked on high in ZipLock® disposable containers in a SharpCarousel (1000 watt) microwave oven at 20 second intervals until aninternal temperature in the centers of the chicken pieces reached 192°F.±3° F. The sample coated with protein powder was cooked to an internaltemperature of 181° F. The cooked chicken pieces were drained on paperplates prior to weighing (two decimal places).

TABLE 7 Difference in chicken Muscle Protein End wgt. Cooking wgt.* (g)isolate (g) Start wgt(g) (g) loss (%) Pct. Pts./% 32.74 0.00 32.74 25.0823.40 control 31.63 4.41 36.04 26.58 26.25 −2.85/89 42.00 0.00 42.0037.53 10.64 control 40.60 5.42 46.02 37.53 12.58 −1.94/85 55.59 0.0055.59 50.69 8.81 control 53.13** 0.87 54.00 49.22 8.85 −0.04/99 *Versuscontrol, not including the weight of the protein isolate **coated usingfreeze-dried protein at pH 5.5.

The pieces containing protein at pH 5.5 appeared in much worse conditionthan the controls. The coating formed a coarse surface with a curdledmilk appearance. Both the coated sample and the control had visiblepooled water around them after cooking. The sample coated withdehydrated protein (pH 5.5) had an acceptable appearance comparable toother dehydrated proteins tested. As in Example 4, this exampleillustrates that a 5.5 pH form of the protein composition is not usefulin the present invention.

EXAMPLE 8 Inject into Chicken (Chicken Protein Isolate pH 2.8 Acid)

Protein isolate from chicken breast myofibrillar and sarcoplasmicproteins was produced according to U.S. Pat. No. 6,005,073 (low pH). Theprotein precipitate obtained at pH 5.5 was readjusted back to pH 2.8using 2 M HCl. The thick consistency solution thus produced contained3.7% protein. Chicken breast pieces to be coated were cut into uniformportions, weighed and injected using a BD 5 ml syringe (25 gauge needle)with different amounts of weighed protein (pH 2.8) solution. Theinjected chicken pieces were cooked on high in ZipLock® disposablecontainers in a Sharp Carousel (1000 watt) microwave oven at 20 secondintervals until an internal temperature in the centers of the chickenpieces reached 170° F.±7° F. The cooked chicken pieces were drained onpaper plates prior to weighing (two decimal places).

TABLE 8 Favorable difference in chicken Protein Start wgt End wgt.Cooking gain* Muscle (g) isolate (g) (g) (g) loss (%) Pct. Pts./% 107.220.00 107.22 100.79 6.00 control 107.19 1.36 108.55 104.38 3.84  2.16/156120.36 13.85 134.21 128.76 4.06 12.98/148 *Versus control, not includingthe weight of the protein isolate

The pieces containing the protein isolate in aqueous acidic solutionwere shiny in appearance and had much greater juiciness and bettermouth-feel than the control. The injected pieces retained their originalsize and shape, whereas the control was very shape distorted. Two of thesamples had higher end weights than their original muscle weights aftercooking. Large pools of moisture were found in the control containersand very little to none in the injected pieces containers.

EXAMPLE 9 Inject into Chicken (Pork Protein Isolate pH 2.8 Acid)

Protein isolate from pork loin myofibrillar and sarcoplasmic proteinswas produced according to U.S. Pat. No. 6,005,073 (low pH). Theprecipitate at pH 5.5 was readjusted back to pH 2.8 using 2 M HCl and0.5% NaCl (w/w). The solution was found to be 2.25% protein. Chickenbreast pieces to be coated were cut into uniform portions, weighed andinjected using a BD 5 ml syringe (18 gauge needle) with protein (pH 2.8)solution. The injected chicken pieces were cooked on high in ZipLock®disposable containers in a Sharp Carousel (1000 watt) microwave oven at20 second intervals for a total of 80 seconds. The internal temperaturein the centers of the chicken pieces reached 176° F. for the control and198° F. for the treated sample. The cooked chicken pieces were drainedon paper plates prior to weighing (two decimal places).

TABLE 9 Favorable difference in chicken Protein Start wgt End wgt.Cooking gain* Muscle (g) isolate (g) (g) (g) loss (%) Pct. Pts./% 61.990.00 61.99 50.79 18.07 Control 56.71 0.79 57.50 54.66  4.94 13.13/366*Versus control, not including the weight of the protein isolate

The piece containing protein isolate was shiny in appearance and hadmuch greater juiciness and better mouth-feel than the control. Theinjected piece retained its original size and shape. A large pool ofmoisture was found in the control container and very little to none inthe injected piece container.

1. The process for retaining moisture in uncooked animal muscle tissue during cooking of the animal muscle tissue which comprises: (a) adding to said uncooked animal muscle tissue a protein mixture selected from the group consisting of an aqueous acidic protein solution, having a pH of about 3.5 or less, of myofibrillar proteins and sarcoplasmic proteins derived from animal muscle tissue, a dry protein mixture of myofibrillar proteins and sarcoplasmic proteins derived from animal muscle tissue obtained by drying said aqueous acidic protein solution and mixtures thereof by an adding method selected from the group consisting of applying said protein mixture to at least one surface of said uncooked animal muscle tissue, mixing said protein mixture with said uncooked animal muscle tissue, injecting said protein mixture into said uncooked animal muscle tissue and a combination of at least two of said adding methods and (b) cooking said uncooked animal muscle tissue and protein mixture from step (a).
 2. The process of claim 1 wherein the protein mixture is applied to at least one surface of said uncooked animal muscle tissue.
 3. The process of claim 1 wherein the protein mixture is applied to all surfaces of said uncooked animal muscle tissue.
 4. The process of claim 1 wherein the protein mixture is mixed with said uncooked animal muscle tissue.
 5. The process of any one of claim 1 or 4 wherein said animal muscle tissue is included in a sausage composition.
 6. The process of claim 5 wherein said pH is between about 2.5 and 3.5.
 7. The process of any one of claim 2, 3 or 4 wherein said protein mixture is mixed with a food additive selected from the group consisting of a breading, a batter, a spice dry rub, cracker meal and mixtures thereof.
 8. The process of claim 7 wherein said protein mixture is substantially free of animal membrane lipids.
 9. The process of claim 8 wherein said uncooked animal muscle tissue is fish.
 10. The process of claim 9 wherein said pH is between about 2.5 and 3.5.
 11. The process of claim 8 wherein said uncooked animal muscle tissue is shellfish.
 12. The process of claim 11 wherein said pH is between about 2.5 and 3.5.
 13. The process of claim 8 wherein said uncooked animal muscle tissue is poultry.
 14. The process of claim 13 wherein said pH is between about 2.5 and 3.5.
 15. The process of claim 8 wherein said uncooked animal muscle tissue is meat.
 16. The process of claim 15 wherein said pH is between about 2.5 and 3.5.
 17. The process of claim 8 wherein said pH is between about 2.5 and 3.5.
 18. The process of claim 7 wherein said uncooked animal muscle tissue is fish.
 19. The process of claim 18 wherein said pH is between about 2.5 and 3.5.
 20. The process of claim 7 wherein said uncooked animal muscle tissue is shellfish.
 21. The process of claim 18 wherein said pH is between about 2.5 and 3.5.
 22. The process of claim 7 wherein said uncooked animal muscle tissue is poultry.
 23. The process of claim 22 wherein said pH is between about 2.5 and 3.5.
 24. The process of claim 7 wherein said uncooked animal muscle tissue is meat.
 25. The process of claim 24 wherein said pH is between about 2.5 and 3.5.
 26. The process of claim 7 wherein said pH is between about 2.5 and 3.5.
 27. The process of any one of claim 1 or 4 wherein said animal muscle tissue is included in a hot dog composition.
 28. The process of claim 1 wherein the protein mixture is injected into said uncooked animal muscle tissue.
 29. The process of any one of claim 1, 2, 3, 4 or 28 wherein said uncooked animal muscle tissue is fish.
 30. The process of claim 29 wherein said protein mixture is substantially free of animal membrane lipids.
 31. The process of claim 30 wherein said pH is between about 2.5 and 3.5.
 32. The process of claim 29 wherein said pH is between about 2.5 and 3.5.
 33. The process of any one of claim 1, 2, 3, 4 or 28 wherein said uncooked animal muscle tissue is shell fish.
 34. The process of claim 33 wherein said shellfish is shrimp.
 35. The process of claim 34 wherein said protein mixture is substantially free of animal membrane lipids.
 36. The process of claim 35 wherein said pH is between about 2.5 and 3.5.
 37. The process of claim 34 wherein said pH is between about 2.5 and 3.5.
 38. The process of claim 33 wherein said protein mixture is substantially free of animal membrane lipids.
 39. The process of claim 38 wherein said pH is between about 2.5 and 3.5.
 40. The process of claim 33 wherein said pH is between about 2.5 and 3.5.
 41. The process of claim 1, 2, 3, 4 or 28 wherein said uncooked animal muscle tissue is poultry.
 42. The process of claim 41 wherein said poultry is selected from the group consisting of turkey, duck, goose, game bird and chicken.
 43. The process of claim 42 wherein said protein mixture is substantially free of animal membrane lipids.
 44. The process of claim 43 wherein said pH is between about 2.5 and 3.5.
 45. The process of claim 42 wherein said pH is between about 2.5 and 3.5.
 46. The process of claim 41 wherein said protein mixture is substantially free of animal membrane lipids.
 47. The process of claim 46 wherein said pH is between about 2.5 and 3.5.
 48. The process of claim 41 wherein said pH is between about 2.5 and 3.5.
 49. The process of any one of claim 1, 2, 3, 4 or 28 wherein said uncooked animal muscle tissue is meat.
 50. The process of claim 49 wherein said uncooked meat is selected from the group consisting of ham, beef, lamb, pork, veal, buffalo and venison.
 51. The process of claim 50 wherein said protein mixture is substantially free of animal membrane lipids.
 52. The process of claim 51 wherein said pH is between about 2.5 and 3.5.
 53. The process of claim 50 wherein said pH is between about 2.5 and 3.5.
 54. The process of claim 49 wherein said protein mixture is substantially free of animal membrane lipids.
 55. The process of claim 54 wherein said pH is between about 2.5 and 3.5.
 56. The process of claim 49 wherein said pH is between about 2.5 and 3.5.
 57. The process of any one of claim 1, 2, 3, 4 or 28 wherein said protein mixture is derived from fish muscle tissue.
 58. The process of claim 57 wherein said protein mixture is substantially free of animal membrane lipids.
 59. The process of claim 58 wherein said pH is between about 2.5 and 3.5.
 60. The process of claim 57 wherein said pH is between about 2.5 and 3.5.
 61. The process of any one of claim 1, 2, 3, 4 or 28 wherein said protein mixture is derived from poultry muscle tissue.
 62. The process of claim 61 wherein said protein mixture is substantially free of animal membrane lipids.
 63. The process of claim 62 wherein said pH is between about 2.5 and 3.5.
 64. The process of claim 61 wherein said pH is between about 2.5 and 3.5.
 65. The process of any one of claim 1, 2, 3, 4 or 28 wherein said protein mixture is derived from meat muscle tissue.
 66. The process of claim 65 wherein said meat muscle tissue is selected from the group consisting of ham, beef, lamb, pork, veal, buffalo, venison and mixtures thereof.
 67. The process of claim 66 wherein said pH is between about 2.5 and 3.5.
 68. The process of claim 65 wherein said pH is between about 2.5 and 3.5.
 69. The process of any one of claim 1, 2, 3, 4 or 28 wherein said protein mixture is substantially free of animal membrane lipids.
 70. The process of claim 69 wherein said pH is between about 2.5 and 3.5.
 71. The process of claim 1 wherein said protein mixture is a dry protein mixture of myofibrillar proteins and sarcoplasmic proteins derived from animal muscle tissue.
 72. The process of claim 1 wherein said protein mixture is an aqueous acidic protein solution of myofibrillar proteins and sarcoplasmic proteins derived from animal muscle tissue.
 73. The process of any one of claim 1, 2, 3, 4, 28, 71 or 72 wherein said pH is between about 2.5 and about 3.5. 